Bogati was admitted to the hospital last Thursday following a severe heart attack as well as brain haemorrhage.
He was hospitalised and underwent a major surgery at the Kathmandu-based Gangalal National Heart Centre before being shifted to Norvic Hospital.
Norvic Hospital had said Bogati's condition had been critical Sunday and he was put on ventilator.
Planning was also under way to airlift the 62-year-old leader to India for advanced treatment.
Bogati had been an active member of Nepal's UCPN (Maoist) party since its inception.
Bogati also held positions as the minister for information and communications, culture, tourism and civil aviation.
Though the UCPN (Maoist) is yet to declare his death formally, the party's senior leader, Baburam Bhattari, has announced his death through Twitter.
"It is very sad that Comrade Post Bahadur has passed away this morning. Condolence to the bereaved soul," Bhattari tweeted.